The deges of a  parallelopied are  of unit  length and  are  parallel  to  non- coplanar  unit  vector `hat(a), hat(b) , hat(c )` such that  `hat(a) , hat(b) = hat(b), hat( c)=hat(c ), hat(a) = .(1)/(2). ` Then  the volume  of the   parallelopiped is
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